你是哪国人？ --> ni shi na guo ren? --> referring to which country are you from? 你是哪里人？ --> ni shi na li ren? ---> referring to which city/province are you from? Not too hard to remember because 国 (guo) means country. So the first sentence literally is: "You are which country person?"

你从哪里来？ni3 cong2 na3 li3 lai2? or 你是哪里人？ni3 shi4 na3 li3 ren2?

你是哪国人？ ni shi na guo ren?

ni cong na li lai?你从哪里来？

你是哪里人？